Work holder crankpin grinder



June 6, 1939. H. A. SILVEN WORK HOLDER CRANKPIN GRINDER Filed April 23, 1958' 3 Sheets-Sheet l gwuc/wbw HERBERT FLEILVEN WMLJMQ Snow;

June 6, 1939. H. A. SILVEN 7 WORK HOLDER CRANKPIN GRINDER Filed April 23, 1938 3 Sheets-Sheet 2 awe whoa, HERBERT H.5ILVEN mum;

5 Sheets-Sheet 3 3 HERBERT H.5ILVEN amw'mn EILEG H. A. SILVEN Filed April 23, 1938 WORK HOLDER CRANKPIN GRINDER June 6, 1 939.

Patented June 6, 1939 UNITE D S TAT E S PATENT OFFICE WORK HOLDER CRANKPIN GRINDER Herbert A. Silven, Worcester, Mass, assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts Application April 23, 1938, Serial No. 203,837

9 Claims.

' 5.; shaft grinding.

One object of the invention is to provide a simple and thoroughly practical clamping mechanism for a work piece. Another object of the invention is to provide a mechanically operated I01 clamping mechanism for a work piece. Another object of the invention is to provide an automatically actuated positive work clamping mechanism. A further object of the invention is to provide a spring actuated positive work clamp 1-5: which ishydraulically released.

A further object of the invention is to provide a nut and screw actuated clamping jaw which is automatically actuated to clamp a work piece therein before a grinding operation and to release 20 it therefrom after the grinding operation has been completed. Another object of theinvention is to provide a work clamping mechanism including a pivotally mounted jaw which is automatically moved into an operating position when a work '25 piece is placed in position on the work holder. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements,

' 30 and arrangements of'parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is 35 shown one of various possible embodiments of the mechanical features of this invention:

Fig. 1 is an end elevation of the improved work clamping and rotating mechanism;

Fig. 2 is a vertical sectional 'view taken approxi- 40 mately on the line 2-2 of Fig. 1, showing the clamping jaw in elevation;

Fig. 3 is -a vertical sectional view taken approximately on the line 33 of Fig. 1, on a reduced scale, showing a fragmentary section 45 through the entire work head to show the spring actuated clamping and the-hydraulic releasing mechanism;

Fig. 4 is a fragmentary sectional view taken approximately on the line 44' of Fig. 1; and

Fig. 5 is a plan view having parts broken away more clearly to show the construction.

The invention provides an automatic clamping mechanism for a grinding machine, such as crankshaft grinding machines and the like, and 55whichisparticularly useful a double headgrinding machine in which two opposed worksupporting heads are'provided with a clamping mechanism to support and to rotate synchronously the opposite ends of the work piece during the grinding operation. In the form illustrated, a clamping device for holding the work during rotation may comprise a rotatable holding member and a clamping jaw which is movable into engagement with the periphery of an end of the work by a power mechanism. The clamping jaw may be moved into an operative position automatically when the workpiece is placed in position on the work holders and is positively rotated by means of a motor driven mechanism during the grinding operation. work driveand the arrangement of the opposed work heads have not been illustrated in detail since such an arrangement is fully disclosed in the prior Patent No. 1,837,342 dated December 22, 1931, and No. 2,113,388. dated April 5, 1938, to which reference may be had for details of disclosure on the work drive mechanism. The double head crankpin grinding machine referred to in the above-mentioned patents and shown in the present drawings comprises a longitudinally 2'5. movable work table 20 which is adapted to slide longitudinally on a V-way and a flat way (not shown) on the base of themachine. The table 20 is adapted to support a work piece, such as a crankshaft 21-, in operative relation with a rotatable' grinding wheel which may be mounted on a wheel slide, such as is in common use and a well known expedient in grinding machine construction. The work table 20 is'provided with a work head 25'or, if desired, 'a pair of opposed work heads arranged on the table 20 in a manner similar to that shown in the prior United States patents above referred to. The work head or heads 25 may be formed integral with the table 20 or may I be adjustably clamped thereon so that the heads may be moved laterally of the table to align the axis of one head relative to the other and may also be adjusted longitudinally on the table so as to accommodate various lengths of crankshafts.

The head 25 is provided with a rotatable work supporting spindle 26 journalled in bearings 21- and 28,. respectively. A sprocket 29 is mounted on the spindle 26 adjacent to one end thereof and is connected by means of a link driving chain 3| 50 with a sprocket 30 which is mounted on one end of a rotatable drive shaft 32. The shaft 32 is mounted in bearings (no-t shown) depending from the table 20. In case the improved work head is utilized in a double head machine, the work head 55.

The particular type of 5':

work heads are provided for supporting and rotating a crankshaft for a grinding operation. The shaft 32 may be rotated in any suitable manner, for example by a mechanism such as that shown in the prior U. S. patents above referred to.

In the grinding of crankpins on a crankshaft,

it is desirable to support the shaft by its end bearing portions which are supported in an offset relationship with the axis of rotation of the work spindles by an amount equal to the throw of the crankpins being ground so that the crankpin being ground may be swung into axial alignment with the work spindle or spindles and clamped in this position for a grinding operation.

An automatic clamping mechanism is utilized which rigidly locks the crankshaft 2! in place during the grinding operation. As illustrated, the inner end of the work supporting spindle 25 is provided with anenlarged face plate 35 to which the pot chuck or work supporting and clamping head 35 is rigidly secured. The head 36 is provided with a fixed work supporting and loeating member 31 which is provided with a partial cylindrical surface 38 to support the periphery of one end of the crankshaft to be ground. In case a double head machine is utilized, the surfaces of the bearing portion adjacent to the ends of the crankshaft are each similarly supported on, a partially cylindrical bearing surface 38 which is fixed to each of the work heads 36 definitely to locate the opposite ends of the crankshaft with relation to the axis of rotation of the opposed work heads and spindles.

The work head or pot chuck 36 is provided with a pivotally mounted clamping jaw 4|]. The clamping jaw 40 is pivotally supported at one end on a stud 4! which is fixedly supported by the work head 36. A work engaging or clamping screw 42 is screw threaded through the pivotally mounted jaw 40 and is positioned to engage the work piece, such as the end bearing of a crankshaft, at a point diametrically opposite from the partially cylindrical surface 38 on the fixed work supporting member 31. A lock nut 43 is provided to lock the screw 42 in the desired adjusted position. The clamping jaw 40 (Fig. 1) is of generally circular shape which is arranged to straddle the work piece 2|. The jaw 40 is provided with two V-shaped notches 44 and 45 at its pivoted end which are arranged to be engaged by a spring-pressed plunger 46. The plunger 46 is supported in the work head 36. A spring 41 serves normally to maintain the arrow pointed top of the plunger 46 either in engagement with the notch 44 or the notch 45 to hold the clamping jaw 45 either in an operating position, as shown in full lines in Fig. 1, or in an inoperative position, as indicated in. dotted lines therein.

In order to attain one of the objects of the invention, a mechanism is provided for automatically swinging the clamping jaw into an operative position when a work piece is placed in position on the work head. The inner end of the stud 4! 'is provided with a projecting arm 48 which carries a pin 49 at its lower end (Fig. 5). When the jaw 40 is in an inoperative position, as shown in dotted line 40a (Fig. 1), the pin 49 lies in the path of a flange 22 which is formed integral with the end of the crankshaft. During the movement of the crankshaft into position on the partially cylindrical supporting and locating surface 38, the flange 22 engages the pin 49 which serves to rock the stud 4| and the cla pparts are duplicated on the other end of the table ing jaw 40 from the position 40a to the full line position 54, as indicated in Fig. 1.

In order to clamp the crankshaft 2i rigidly in position on the work head 36, it is desirable to provide a clamping mechanism to secure the outer end of the jaw 45 in rigid engagement with a fixed portion of the work head 35. In the preferred form, this is accomplished by a nut and screw mechanism which is automatically actuated to clamp and release the jaw 45 in timed relation with the other mechanisms of the machine. As illustrated in the drawings, a stud or screw 50 extends through an aperture 54 in the lefthand end portion of the jaw 45] (Fig. l). The stud 50 is slidably keyed therein by means of a key 52. The upper end of the stud 55 is provided with a threaded portion 54 which is engaged by a nut 55. The lower end of the stud or screw 50 is provided with a substantially square-shaped head 56 which is provided with a substantially square-shaped aperture 57 the lower surface of which is provided as an inclined plane 58 which is adapted to be engaged by means of a wedgeshaped plunger 59. A spring 58 surrounding the stud 5B and interposed between the head 55 of the stud and a recessed aperture 6! within the end portion of the jaw 40 serves normally to hold the head 55 and stud 5% in a downward position.

The main bearing surfaces on the ends of a crankshaft, when the shaft is presented for the grinding of the crankpins, vary somewhat in size. In order to compensate for variations in diameters of the end bearings of the shaft, the wedge shaped plunger 59 is employed. The spring pressed plunger, being wedge shaped and arranged to engage the inclined surface in the aperture 51, serves to compensate for any variations in the diameter of the bearing surface supported in the chuck. This wedge takes up the slack in the bolt so that when the nut 55 is automatically rotated, the same clamping pressure will be exerted upon the shaft regardless of any slight variations in the diameter of the bearing support.

The wedge-shaped plunger 59 is mounted in a horizontally extending cylindrical aperture 63 within the head 38 and is normally urged in a direction toward the right (Fig. 2) by means of a compression spring 54. The wedge-shaped plunger 59 serves as a detachable connection to lock the bolt or stud 50 in an operating position during a grinding operation, as shown in Figs. 1 and 2, or to release it therefrom so as to permit the clamping jaw 45 to swing to an inoperative position for removing a finish ground shaft therefrom and replacing it with a new shaft to be ground. The plunger 55 is arranged so that it may be automatically withdrawn from engagement with the aperture 5? and the inclined surface 58 so as to release the stud or screw 50 after a grinding operation has been completed. The wedge-shaped plunger 63 is provided with opposed slabbed-oif surfaces 64 and 65 which are engaged by a yoke-shaped member 66 formed at the outer end of a lever 61. The lever B"! is pivotally mounted on a stud 68 supported on the head 36. The lever 5'! is arranged so that it may be swung automatically by a mechanism to be hereinafter described in order to withdraw the spring-pressed Wedge-shaped plunger 57 after a grinding operation has been completed. The spring-pressed Wedge 59 serves to engage the inclined surface 58 in the aperture 5'5 so as to lock the lower end of the clamping stud or screw 5E! rigidly to the head 28 in an operating position.

To obtain one of the objects of the invention, it is desirable to provide a mechanism for automatically actuating the clamping jaw, which is preferably accomplished automatically actuating the nut 55 to clamp and release a work piece in the work head. The nut 55 is preferably provided with an integrally formed lever or arm Ill which is provided with a downwardly extending stud -H. The stud "H rides in a groove 12 formed in a plate 13 which is fixedly mounted to a flange 14 by means of screws 14a. The flange 14 is preferably formed integral with a rod 15 which extends axially within the hollow spindle 26. A spring 16 surrounding the rod 15 and interposed between a shoulder I l on the rod 15 and a shoulder 18 formed integral with the spindle 26 serves normally to urge the rod '5 in a direction toward the right (Fig. 2') which serves to move the plate "l3 and groove '12 toward the right (Fig. 2) so as to rock the arm Ill to turn the nut 55 and thereby rigidly clamp the outer end of the jaw 40 relative to the work head 36.

A fluid pressure piston 80 is mounted on an outwardly extending portion of the rod 15 and is slidably mounted within a fluid pressure cylinder 8| which is fixed to the end of the work head 25.

When fluid under pressure is admitted through a pipe 82 into a cylinder chamber 83, the piston 85 and 'rod 15 are moved in a direction toward the left (Fig. 3) which serves to rotate the nut 55 in the opposite direction to unclamp the outer end of the jaw 40. The lever 6-! "is provided with an adjustable actuating screw or stud 85 which is screw threaded through the lever and locked in adjusted position by means of a nut 86. The lower surface of the rod 15 is slabbed off, as indicated in dotted lines 88 in Fig. 2. When the rod 15 is moved toward the left (Figs; 2 and 3) to slack off the 'nut "55 to unclamp the jaw '40, the shaft travels a slight distance after which a shoulder 8}! of a recess in the rod '15 engages the head 90 of the screw 85 and causes the screw to rock the lever '61 in a clockwise direction (Fig. 4) to move the spring-pressed wedge '59 toward the left to withdraw it from the aperture 51 and thereby release the screw '50 and the outer end of the clamping jaw 40 so that the crankshaft supported therein may be lifted from the holder. Withdrawal of the crankshaft from the holder causes the clamping jaw 40 to swing in a counterclockwise direction (Fig. 1) into the dotted position 40a so that the spring-pressed plunger 46 engages the notch 45 in the lever 40 to hold the jaw 40 in an inoperative position during the loading or indexing operation.

If desired, the piston 80 may be moved under the influence of fluid pressure in both directions to move the rod 15 and actuate the clamping nut 55 both to clamp and. release a crankshaft. A port 8201, is provided to admit fluid under pressure to the left-hand cylinder chamber 83a.

The operation of this improved work supporting and clamping head will be readily apparent from the foregoing disclosure. A crankpin 2| to be ground is placed in position on the partial cylindrical work supporting and locating surface 38. When the shaft is placed in this position, the flange 22 on the end of the crankshaft to be ground engages a pin 49 which serves to rock the clamping jaw 40 from the dotted line position Gila/into the full line position 40 (Fig. 1). The main control lever, 'such as that shown in the prior United States Patent Nos. 1,837,342 and 2,113,388, is then shifted to allow fluid within the cylinder chamber B3 to exhaust through the pipe 82, thereby releasing the compression of the spring 15, which causes the rod 15 to move toward the right (Figs. 2 and 3 The movement of the rod toward the right serves through the rock arm 51 to release the compression of the spring 64 which moves the spring-pressed wedgeshaped plunger 59 into the aperture 51 so that the wedge surface 59 engages the inclined surface '58 to lock the head "56 of the clamping bolt 55 in an operatingposition on the head 35. Continued movement of therod 15 toward the right (Fig. 2) serves to rock the arm 10 in a clockwise direction (Fig. 5) to rotate the nut 55 also in a clockwise direction to tighten the clamping bolt- .55 so that the jaw 4'0 is locked with the clamping screw :42 rigidly holding the shaft 2i in position on the partial cylindrical supporting and locating surface 38 for a grinding operation. After a grinding operation has been completed, the control lever is shifted to admit fluid under pressure through the pipe 82 into the cylinder chamber 83 to cause the piston 80 and the rod R5 to move toward the left '(Fig. 3) which serves first automatically to rotate the nut 55 to release the clamping jaw 40 and then automatically to withdraw the spring-pressed wedge 59 so that the crankshaft 2 may be readily lifted from the machine. The lifting of the shaft from the ma chine serves to lift the clamping jaw 40 to an inoperative position and the spring-pressed plunger 18 holds the jaw 48 in an inoperative or open position until the next half is placed in the machine.

It will thus be seen that there has been pro- 2 'vi-d'ed by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments-may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that -all matter hereinbefore set forth or shown 'in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim. 7

1. A pot chuck for a crankpin grinding machine havinga rotatable head, a partial cylindrical bearing surface fixedly mounted onsaid head and arranged to support and locate a workpiece thereon, a pivotally mounted clamping jaw, a stud pivotally connecting one end of said jaw to said head, and automatically actuated clamping mechanism to clamp the other end of said jaw to said head to secure a work piece in an operative position.

2. A pot chuck for a crankpin grinding machine having a rotatable head, a partial cylindrical bearing surface fixedly mounted on said head and arranged to support and locate a work piece thereon, a pivotally mounted clamping jaw,

a stud supporting one end of said jaw, a detachthe work piece, a nut and screw mechanism arranged to actuate said jaw, a spring actuated mechanism operatively connected to actuate said nut and screw to operate said jaw rigidly to clamp the work on said head, and a fluid pressure mechanism including a piston and cylinder operatively connected to actuate said nut and screw to move the clamping jaw to release the work.

4. A pot chuck for a crankpin grinding machine having a rotatable head, a partial cylindrical bearing surface fixedly mounted on said head and arranged to support and locate a work piece thereon, a pivotally mounted clamping jaw, a stud supporting one end of said jaw, a nut and screw carried by the other end of said jaw, a spring-pressed plunger automatically and detachably to lock said screw to said head, and spring actuated means to turn said nut to clamp the jaw in an operating position.

5. A pot chuck for a crankpin grinding machine having a rotatable head, a partial cylindrical bearing surface fixedly mounted on said head and arranged to support and locate a work piece thereon, a pivotally mounted clamping jaw, a stud supporting one end of said jaw, a nut and screw carried by the other end of said jaw, a spring-pressed plunger automatically and detachably to lock said screw to said head, spring actuated means to turn said nut to clamp the jaw in an operating position, and means including a hydraulically operated piston and cylinder mechanism to actuate said nut in the opposite direction to release said jaw.

6. A work supporting and rotating mechanism for a grinding machine comprising a rotatable spindle, a work supporting head mounted on said spindle, a clamping jaw on said head, means including a nut and screw on said head to operate said jaw, a rod passing through a central aperture in said spindle, connections between said rod to actuate said nut and screw, a spring operatively connected to move said rod in one direction to actuate the nut and screw to clamp said jaw, and a fluid pressure mechanism including a piston and cylinder operatively connected to move said rod in the opposite direction to actuate said nut and screw to release said jaw.

'7. A pot chuck for a crankpin grinding machine comprising a rotatable head, a partial cylindrical bearing member fixedly mounted on said head and arranged to support and locate a crankshaft thereon, a clamping jaw opposed to said bearing surface, a stud on said head pivotally to support one end of said jaw, means including a nut and screw mounted in the other end of said jaw, a spring actuated wedge detachably to connect one end of said screw to said head, means including an axially movable spindle within said head, a lever to turn said nut and operatively connected to move with said spindle, means including a spring to move said spindle axially to actuate said nut and clamp said jaw in an operating position, and means including a piston and cylinder operatively connected to move said spindle in the reverse direction to unclamp said nut and jaw and to withdraw said spring actuated wedge.

8. A pot chuck for a crankpin grinding machine having a rotatable head, a partial cylindrical bearing surface fixedly mounted on said head and arranged to support and locate a crankshaft thereon, a pivotally mounted clamping jaw, a stud supporting one end of said jaw, a projection on said jaw which is engageable by said work piece automatically tomove the jaw to an operative position when a crankshaft is inserted in the chuck, a nut and screw carried by the other end of said jaw, a spring pressed plunger automatically and detachably to lock said screw to said head, and automatically actuated means to turn said nut to clamp the jaw in an operating position.

9. A pot chuck for a crankpin grinding machine having a rotatable head, a partial cylindrical bearing surface fixedly mounted on said head and arranged to support and locate a crankshaft thereon, a pivotally mounted clamping jaw, a stud supporting one end of said jaw, a spring pressed detent arranged to hold said jaw either in an operative or an inoperative position, a projection on said jaw which is arranged to be engaged by a crankshaft when the same is inserted in said chuck automatically to move said jaw to an operative position, a nut and screw carried by the other end of said jaw, a spring pressed plunger automatically and detachably to lock said screw to said head, and automatically actuated means to turn said nut to clamp the jaw in an operating position.

HERBERT A. SILVEN.

CERTIFICATE 0F CORRECTION.

Patent No. 2,161,206. June 6, 19 9.

HERBERT A. SILVER. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, sec-- ond column, line 55, for the word '"half" read shaft; and'that the said Letters Patent sho'uldbe read with this correction thereintha-t the same may conform to the record of the case inthe Patent Office. 7 I

Signed and sealed this 22nd day of August, A. D. 1959.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

